The present invention relates to a system for analyzing a suspension system. More particularly, the present invention relates to a system, in which, to enable better analysis of the manner that wheel movement characteristics (e.g., camber, toe, and caster) in an independent suspension system are affected by a mounting position and length of each link in a steering system and suspension system, the mounting position and length of the links may be varied as desired to allow visual observation of the wheel movement characteristics.
Vehicles generally include a suspension system that is mounted between the vehicle frame and wheels. The connection to the frame and wheels is realized through links, and the suspension system acts to absorb shocks and vibrations received from the road through the wheels, thereby improving comfort and safety. In more detail, the suspension system includes springs and shock absorbers for cushioning shocks and vibrations in a generally vertical direction, and various arms and rods for providing additional support in the same and other directions by providing a suitable combination of rigidity and elasticity.
The suspension system as structured in the above is required to perform a variety of functions. First, the suspension system must provide comfort to passengers by absorbing shocks. Second, side-to-side rocking of the vehicle, resulting from abrupt steering operations by the driver or when driving on a curve, must be minimized by the suspension system to thereby provide comfort and better control over the vehicle by the driver. Third, it is necessary that the suspension system exert a downward force such that a suitable degree of contact force is maintained between the tires and road surface, thereby enhancing safety, particularly when cornering or braking.
Drive comfort and stability are affected by the weight of the vehicle, distribution of the weight of the vehicle, road conditions, tire and wheel alignment, and the suspension system. In addition, the suspension system, together with the steering system, greatly affects handling (i.e., turning, tracking, and cornering performance). A large variety of different types of suspension systems have been developed, all with the goal of optimally providing the required functions of the suspension system. Relatively recently, there has been an increased need for high-performance suspension systems that are more responsive so as to better meet demands for enhanced performance by consumers, and to better suit the ever more powerful sports vehicles that are being developed.
The independent suspension system was developed out of such demands. The different types of independent suspension systems include the Macpherson suspension system, which is structurally simple and lightweight, and in which struts that determine the positioning of wheels are used as shock absorbers; the double wishbone suspension system, which is somewhat expensive but suitable for application to high-performance vehicles with its A-type arms; and the multi-link suspension system, which is similar to the double wishbone suspension system but uses a plurality of links.
Such independent suspension systems are structurally complicated such that it is difficult to determine how characteristic wheel movement (e.g., camber, toe, and caster) is affected during steering and bouncing. In the prior art, a system has been developed that enables visual analysis of only one such movement characteristic at a time, such as camber variations during steering. That is, with reference to FIG. 7, an analysis system 601 provides a model in which a wheel 603 is fixed to a kingpin shaft (shock absorber) 605 to make observations such as changes in camber.
However, in order to maximize the drive stability, handling, and ride comfort of the independent suspension system, a three-dimensional model is needed to more concretely and simply understand the structural characteristic movements of the independent suspension system. But there has not been any development of testing or analysis equipment that realize all the structural movements of the independent suspension system.
Further, analysis systems that can realize all the geometric characteristics during steering and bouncing in typical independent suspensions system such as the double wishbone, Macpherson strut, and multi-link suspension system have not been developed.
According to a preferred embodiment of the present invention, a system is provided for analyzing a suspension system comprising: a frame assembly including a plurality of frame units, a base plate, a lower mounting unit, and an upper mounting unit; a wheel assembly including a wheel member that functions as a wheel, and a wheel mounting assembly for enabling mounting of the wheel member to the upper and lower mounting units of the frame assembly through a suspension; a steering assembly provided to one side of the frame assembly and being connected to the wheel mounting assembly of the wheel assembly, the steering assembly performing a steering function through a rack-and-pinion operation; a strut assembly including a shock absorber and a suspension spring and being provided between the wheel assembly and the frame assembly, the strut assembly being able to undergo variations in mounting positions and length between its connection to the wheel mounting assembly of the wheel assembly and the upper mounting unit of the frame assembly; and an arm assembly including a plurality of arms and links and being provided between the wheel assembly and the frame assembly, the arm assembly being able to undergo variations in mounting positions and length between its connection to the wheel mounting assembly of the wheel assembly and the lower mounting unit of the frame assembly.
In a preferred embodiment of the present invention, the frame units of the frame assembly comprise: first and second frame units provided in parallel at a predetermined distance; a third frame unit interconnecting the first and second frame units; and fourth frame units provided extending upward from (i.e., substantially perpendicular to) each of the first and second frame units, and wherein the base plate of the frame assembly is provided on top of the fourth frame units and comprises: first and second skirts that extend downward from longitudinal edges of the base plate and which are fixed to the fourth frame units; a pair of receiving slots formed at a predetermined spacing in each of the skirts and which act as a guide for the lower mounting unit; an integrally formed section that extends outward from substantially an upper face of the base plate and perpendicular to the second skirt, on which the steering assembly is provided; guide housings mounted on opposite sides of the base plate extending vertically upward; and slide bars slidably provided in the guide housings and able to be fixed at a desired position therein using bolts that pass through bolt holes formed in the guide housings.
In a further preferred embodiment of the present invention, the upper mounting unit is provided on upper ends of the slide bars and comprises a mounting plate that extends from one slide bar to the other and is fixed to upper ends thereof; and adjustable mounts, each of which is fixed to an opposite end of the mounting plate, one end of each of the adjustable mounts including one connecting slot and a pair of slide slots for enabling fixing and position adjustment on the mounting plate, and connecting slots being formed on opposite ends of the adjustable mounts to which the strut assembly is connected.
According to yet another embodiment of the present invention, the lower mounting unit is realized through an arm connecting plate that passes through one of the receiving slots in the skirt and a corresponding receiving slot in the opposing skirt, the first arm connecting plate including connecting slots that are formed at a predetermined length along a longitudinal direction of the arm connecting plate and on both ends thereof, and the arm connecting plate including a threaded bolt hole at a center position thereof, a bolt being screwed into the bolt hole until making close contact with the base plate to fix a position of the arm connecting plate.
According to still yet another embodiment of the present invention, the wheel member of the wheel assembly is a circular plate made of a transparent plastic material.
According to still yet another embodiment of the present invention, the wheel mounting assembly of the wheel assembly comprises: a connecting bracket, which is coupled to the wheel member through a plurality of bolts at a position slightly below a center of the wheel member; a knuckle bracket, which is connected to the wheel member through a plurality of bolts at a position slightly above the center of the wheel member, a lower end of the strut assembly being connected to the knuckle bracket; and a knuckle plate fixed to a rear portion of the knuckle bracket and having a slot for connection with the steering assembly.
According to still yet another embodiment of the present invention, the steering assembly is mounted on the base plate on the section extending outwardly from the second skirt and comprises: a rack bar that extends in a longitudinal direction of the base plate, and which undergoes rectilinear motion while being guided by a guide, the rack bar including a rack segment that is formed at a center thereof and at a predetermined length with adjustable segments formed on both ends of the rack bar; a pinion meshed with the rack segment of the rack bar; a rotating bar passed through a center of the pinion, one end of the rotating bar being rotatably connected to a support bracket, which is fixed to the base plate, and a control knob being formed on its other end; and a knuckle arm connected via a universal joint to each extreme end of the rack bar, ball joints being provided at the ends of the knuckle arms, the ball joints corresponding to the side of the system being used and being connected to the wheel mounting assembly of the wheel assembly.
According to still yet another embodiment of the present invention, the adjustable segments of the rack bar comprise: a hollow tube that has a groove of a large width formed along a predetermined length of the hollow tube; and a rod, a majority of which is slidably provided within the hollow tube, a threaded bolt hole being formed in the rod, and a fixing bolt being screwed into the bolt hole via the groove of the hollow tube.
According to still yet another embodiment of the present invention, the shock absorber of the strut assembly comprises: a housing, which is a hollow tube and includes a lower spring seat integrally formed on an upper end thereof; a piston rod passed through the lower spring seat into the housing such that the housing is able to undergo variations in position such that a length between its connection to the wheel mounting assembly and the upper mounting unit of the frame assembly; and a upper spring seat integrally formed to an upper end of the piston rod, and wherein the suspension spring of the strut assembly is interposed between the lower spring seat and the upper spring seat, and is made of a plastic material.
According to still yet another embodiment of the present invention, the arm assembly comprises: an A-shaped arm link, which includes a plurality of slots and is connected to the wheel mounting assembly of the wheel assembly through a ball joint; and a plurality of adjustable arms connected to the slots of the A-shaped link through ball joints, opposite ends of the adjustable arms being connected to the lower mounting unit of the wheel assembly through ball joints, the adjustable arms able to undergo variations in length.
According to still yet another embodiment of the present invention, each of the adjustable arms comprises a hollow tube; threaded inserts of a predetermined length fixed within opposite ends of each of the adjustable arms; bolts screwed into the threaded inserts, the ball joints connected to the A-shaped link being integrally formed to distal ends of the bolts, the threading of the bolts in relation to the inserts being such to allow the length of the adjustable arms to be varied by manually rotating the hollow tube portion of the adjustable arms.